Simulation And Prediction Of The Influence Of Foundation Pitfall Precipitation On The Settlement Of Surrounding Buildings

The foundation pit project is a comprehensive project that involves the mutual influence of various disciplines such as soil mechanics,material mechanics,hydrogeology,fluid mechanics,and engineering geology.With the accelerating pace of urbanization,more and more deep foundation pit projects have appeared in areas where buildings are more dense.In order to ensure that the work surface is clean and tidy,it is necessary to reduce the groundwater level below the design elevation of the bottom of the foundation pit.This will cause changes in the groundwater level around the foundation pit,which in turn will cause subsidence of buildings around the foundation pit.If improper treatment measures will cause The buildings around the pit have hidden dangers and caused extremely bad social impact.Therefore,it is especially necessary to carry out the simulation and prediction of the settlement of the surrounding buildings by the construction of the foundation pit.Based on the actual precipitation of a foundation pit in Kunming City,the paper uses the Midas GTS finite element analysis software to establish a three-dimensional stress-infiltration coupling model,and analyzes the groundwater seepage and the settlement of buildings around the pit during precipitation.At the same time,with regard to the problem that the stratigraphic parameters are too complex,the mathematical model is applied to predict the settlement of surrounding buildings during precipitation.The main research contents and results are as follows:(1)A three-dimensional stress-infiltration coupled model was established using Midas GTS finite element software.The analysis results showed that the error between the simulated value and the monitored value ranged from-5.56% to 11.12%.(2)According to the seepage coupling theory,the influence of the change of insertion depth of the water stop curtain on the settlement of surrounding buildings during the dewatering process of the foundation pit was analyzed.The analysis results show that when the insertion depth of the water stop curtain is divided into 0m,3m,6m,9m,10 m,11m and 12 m,the average settlement of buildings around the foundation pit is reduced from 39.28 mm to 28.09 mm.With the increase of the insertion depth of the water stop curtain,the decline rate of the settlement is gradually reduced,and the influence of precipitation on the soil is gradually reduced,and the impact range is reduced from 36 m to 16 m.(3)In the presence of a water stop curtain,the impact of precipitation on the settlement of the buildings surrounding the foundation pit is analyzed by changing the sensitivity of precipitation depth,precipitation velocity,precipitation patterns,and soil parameters.The results show that in order to ensure the safety of the buildings around the foundation pit in the precipitation process,a waterproof curtain must be added to the strong permeable layer,and adjusting the precipitation depth and precipitation method can effectively reduce the settlement of buildings around the foundation pit.(4)In the case that the stratum parameters are too complex,the finite element software cannot effectively simulate the actual project,and the MAPSO-LSSVM mathematical model is used to predict the settlement of the buildings around the foundation pit after the precipitation is completed.The simulated and measured values are calculated.The error range is between 0.82% and 1.02%.The higher prediction accuracy indicates that the mathematical model can effectively solve practical engineering problems.